The present invention relates to a light curtain device for use in industrial applications such as part measurement, part verification, part inspection and/or part profiling.
Light curtains have a number of known applications. For example, light curtains are commonly employed in industrial applications to perform a variety of measurement and inspection functions. Light curtains are often used in order to size parts, verify part features such as edges, holes and other distinguishing characteristics, and for verification of part ejection and bin picking. Light curtains may also be used on many types of industrial machinery, such as punches, presses, drills, saws, etc., in order to sense the presence of foreign objects and, further, are often found on security and/or safety systems. A number of other industrial applications also are well known.
Light curtain devices typically employ a number of light beams that are disposed to fan out across a designated location in a production line. Typically, such devices employ a plurality of active elements on both sides of the area to be monitored. For example, a plurality of light generators, each of which generates a light beam or column, may be disposed on one side of the monitored area, and a corresponding plurality of light detectors may be disposed on the other side of the monitored area. The interruption of one or more of the light columns thus indicates, for example, the presence of a part at the monitored area, and tracking of which light columns are interrupted can be used, for example, to determine the type or orientation of the part at the monitored location.
The following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
In accordance with a first aspect of the invention, a device for creating a curtain of light between a first location, the first location having a reflector, and a second location, includes a light source adapted to provide a light column, a plurality of beam splitters, and a plurality of light detectors. The beam splitters are disposed to intersect the light column at intervals, and each of the beam splitters is adapted to direct a deflected portion of the light column toward the first location. The reflector adjacent the first location is positioned to receive the deflected portion of the light column from each of the beam splitters. The reflector reflects each deflected portion toward the second location. A plurality of light detectors is disposed adjacent the second location, with each of the light detectors being operatively associated with a corresponding one of the beam splitters and being positioned to receive its corresponding deflected portion reflected by the reflector.
In further accordance with a preferred embodiment, the light source is a vertical cavity surface emitting laser and can be adapted to provide a pulsing light column, while the reflector can be a retroreflector stripe. A collimating lens can be positioned to intersect the light column. Preferably, an additional light detector is positioned to intersect and monitor the condition of the light column. Indicators arranged to indicate the interruption of the light paths can be provided.
The beam splitters can comprise glass elements, such as generally planar glass elements, and can be disposed at a predetermined angle relative to the light column. The glass elements can be coated and will preferably provide reflection of about 8 percent. Preferably, each of the beam splitters will have a coating adapted so that the deflected portion directed by each of the beam splitters will have a similar relative intensity. The glass elements further can have a thickness in the range of about 0.25 mm to about 1.0 mm. Alternatively, the glass elements can be sawn Pyrex(copyright) wafers having a thickness of about 0.25 mm, although other dimensions can work, as will become apparent to those skilled in the art. A collimating lens can be associated with each of the light detectors.
In accordance with another aspect of the invention, a device for creating a curtain of light between a first location and a second location includes a light source adapted to provide a light column and at least one beam splitter disposed to intersect the light column, with the beam splitter being arranged to deflect at least a portion of the light column toward the first location. A reflector is disposed adjacent the first location in a positioned to receive the deflected portion of the light column from the beam splitter, with the reflector being arranged to reflect the deflected portion toward the second location. A light detector is disposed adjacent the second location in a position to receive the deflected portion of the light column reflected by the reflector, and an indicator is arranged to indicate the interruption of the deflected portion of the light column.
In accordance with a further aspect of the invention, a device for creating a curtain of light between a first location and a second location includes a light source adapted to provide a light column, a plurality of beam splitters disposed to intersect the light column at intervals, with each of the beam splitters being adapted to direct a portion of the light column toward a corresponding reflector disposed adjacent the first location, and with each reflector being adapted to reflect the portion of the light column toward a corresponding light sensor disposed adjacent the second location. An indicator is arranged to indicate the interruption of any one of the one or more of the deflected portions.
In accordance with yet another aspect of the invention, a device for creating a plurality of light beams between a first location and a second location comprises a single active light source adapted to provide a main light column, a plurality of beam splitters disposed to intersect the main light column, one or more reflectors disposed generally adjacent the first location, and one or more light detectors disposed generally adjacent the second location. Each of the beam splitters is spaced at intervals along the main light column, with each of the beam splitters being adapted to split a portion of light from the main light column and to direct its split portion of light toward the first location. Each of the one or more reflectors is positioned so that each split portion of light from the light column is reflected toward the second location. Each of the one or more light detectors is positioned so that each split portion of the light column is received by a corresponding one of the light detectors. Each of the light detectors is arranged to indicate the interruption of at least any one of the split portions.
In accordance with a still further aspect of the invention, a device for creating a curtain of light between a first location and a second location comprises a light source adapted to provide a light column along a first path, and first and second beam splitters. Each of the beam splitters is disposed at intervals along the first path to intersect the light column. The first beam splitter is adapted to direct a portion of the light column toward the first location along a second path, and the second beam splitter is adapted to direct a portion of the light column toward the first location along a third path. A reflector is disposed adjacent the first location and is positioned to intersect the second and third paths. The reflector is adapted to direct a portion of the light column toward the second location along a fourth path, and is further adapted to direct a portion of the light column toward the second location along a fifth path. A light detector is positioned to intersect the fourth and fifth paths.
The novel features of the present invention will become apparent to those of skill in the art upon examination of the following detailed description of the invention or can be learned by practice of the present invention. It should be understood, however, that the detailed description of the invention and the specific examples presented, while indicating certain embodiments of the present invention, are provided for illustration purposes only; because various changes and modifications within the scope of the invention will become apparent to those of skill in the art from the detailed description of the invention and claims that follow.